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Bistorta spp.

bistorts

Polygonaceae

Temperate Northern Hemisphere: Europe, Asia, and North America

Attracts Pollinators Attracts Butterflies Deer Resistant Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterMedium

HardinessZones 3–8

Overview

Bistorta spp. is a genus of about 40 species of rhizomatous perennial herbs in the knotweed family, native to cool temperate and mountain regions across the Northern Hemisphere. Plants spread by thick, often contorted rhizomes to form clumps of long-stalked, oval to lance-shaped basal leaves, above which rise unbranched stems 1 to 4 feet (30 to 120 cm) tall. Each stem ends in a dense, cylindrical, bottlebrush-like spike of tiny flowers, usually pink but sometimes white or red, 1 to 4 inches (2.5 to 10 cm) long. Common bistort (B. officinalis) blooms in late spring, while B. amplexicaulis flowers from summer into fall. The young leaves and rhizomes of some species are eaten as cooked greens and were once a traditional food. The genus needs reliably moist soil and declines in hot, dry sites, and the spreading rhizomes can crowd smaller neighbors.

Native Range

Bistorta spp. is native across the temperate and subarctic Northern Hemisphere, including Europe, northern and central Asia, and North America. Species grow in damp meadows, streamsides, mountain grassland, and open woodland, often where the soil stays moist through the growing season. Several alpine species occur high in mountain ranges.

Suggested Uses

Grown in moist borders, bog and streamside plantings, wildflower meadows, and cottage gardens, where the spikes draw bees and butterflies. Taller forms are used in the middle of borders and as cut flowers. Plants are spaced 18 to 24 inches (45 to 60 cm) apart in groups.

How to Identify

Recognized by clumps of long-stalked basal leaves and slender, unbranched stems each topped by a single dense, cylindrical flower spike resembling a bottlebrush. The spikes are packed with small five-parted pink or white flowers. The rhizomes of common bistort are characteristically S-shaped or twice-bent, the feature that gives the genus its name.

Appearance

Size & Dimensions

Height1' - 4'

Width/Spread1'6" - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~10 weeks

Spring Summer Fall

Flowering depends on species and spans late spring through fall, broadly May to September. Common bistort (B. officinalis) peaks in late spring and early summer, while B. amplexicaulis and its forms flower over many weeks from midsummer into autumn. Removing spent spikes prolongs flowering in the long-flowering species.

Detailed Descriptions

Flower Description

pink, sometimes white or red

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

loam clay

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

Reaches mature clump size in 2 to 3 years

Care & Maintenance

Care Guide

Plants grow in full sun to part shade and need moisture-retentive soil that does not dry out; growth and flowering suffer in hot, dry positions. A fertile loam or clay enriched with organic matter suits the genus, and plants tolerate heavy soils and damp ground. Clumps are long-lived and need little care once established, spreading steadily by rhizomes. Congested clumps are lifted and divided in spring or fall to renew vigor and control spread. Foliage may develop powdery mildew or rust in dry conditions or where air movement is poor.

Pruning

Pruning is limited to cutting back spent flower stems to tidy the clump and encourage rebloom in the longer-flowering species. Foliage is cut to the ground after it dies down in late fall. Crowded clumps are divided every few years.